Issues with compiling for target aarch64-unknown-linux-musl

[whatyouhide]

Hey all! I've been having an awesome time trying Rustler and rustler_precompiled out 🙃 I'm using them for an LZ4 compression/decompression library for Elixir that uses Rust bindings (I tweeted about this just yesterday).

I’m having one small issue, and I suck at Rust so I figured maybe I’m just doing something dumb. I have an M1 Mac and I am doing some testing in an Alpine Docker container. This means that the target I’m looking for should be aarch64-unknown-linux-musl.

If I try to add this target to the GitHub Actions example you folks provide in the documentation, it doesn't seem to build (see this build), spitting out this error:

error: cannot produce cdylib for `nimblelz4 v0.1.0 (/project)` as the target `aarch64-unknown-linux-musl` does not support these crate types

Have you folks stumbled across this?

By the way, the reason I’m going through these tribulations is that I’m having issues with making the x86_64-unknown-linux-musl target working as you can see in this build from a package that uses the RustlerPrecompiled package as a dependency.

Thanks in advance! 💟

[whatyouhide]

I tried adding this to my native/<package>/.cargo/config too, with no luck:

# See https://github.com/rust-lang/cargo/issues/7154
[target.aarch64-unknown-linux-musl]
rustflags = [
    "-C", "target-feature=-crt-static"
]

[adriankumpf]

I ran into the same issue when trying to compile aarch64-unknown-linux-musl for mail_parser. Installing the latest unreleased version of cross did the trick: https://github.com/kloeckner-i/mail_parser/blob/f4af5083aec73a47f0e41a202ba46a91f60602cf/.github/workflows/release.yml#L101-L105

[philss]

@whatyouhide I'm glad to see that you are using and enjoying rustler_precompiled! :smiley:

But sorry, I don´t know exactly what can be :/ Probably updating cross can help - btw, thanks @adriankumpf :purple_heart: ! -, but since you have issues with x86_64-unknown-linux-musl, this may not be the case.

I did, however, encounter a similar problem while trying to use a compiled artifact on Linux using musl: the custom malloc lib didn't work there. So I had to disable it. Please check this PR: https://github.com/elixir-nx/explorer/pull/240 So maybe it's something in your dependencies that is causing the issue. I'm going to check that.

[philss]

@whatyouhide I was able to compile and run the NIF on Linux with musl (x86_64-unknown-linux-musl). I don't know if I got correctly, but you did fix the issues for that target, right?

[philss]

Btw, I'm using this Dockerfile to test at the root dir of nimble_lz4 - :

FROM hexpm/elixir:1.13.4-erlang-24.3.4-alpine-3.15.3

WORKDIR /app
RUN apk update && \
    apk upgrade --no-cache && \
    apk add --no-cache \
    git \
    curl \
    build-base \
    libgcc \
    openssl-dev

RUN mix local.hex --force && mix local.rebar --force

COPY . .

After that I enter the container and install Rust before running the tests:

docker build -t lz4_first .
docker run -it --rm lz4_first /bin/sh

Once inside the container, I install Rust before running mix test:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

[whatyouhide]

Hey folks! Thanks for all the responses.

@adriankumpf's suggestion to use the latest version of cross is what did the trick. I opened up https://github.com/philss/rustler_precompiled/pull/22 to mention that in the docs.

@philss I was already able to make x84_64-unknown-linux-musl work, it worked out of the box 🤓 The one giving me trouble was aarch64-unknown-linux-musl (basically, Alpine Docker containers running on M1 Mac for me).

Thanks everyone! 💟